Northwest-side drivers are adding a new term to their vocabulary this week — the Michigan left.

Over the last two days, Pima County started requiring drivers on West Ina Road to make what is also called an indirect left or “Michigan loony” onto North Oracle Road.

The Michigan left requires drivers to go through the Oracle intersection to the next stoplight — one block down — where they can make a turn-arrow-protected U-turn before doubling back to Oracle and making a right turn.

It’s the first intersection of its type for Tucson but not the last. A similar intersection is planned for West Grant Road and Oracle when that project is finished in a month or so.

Priscilla Cornelio, the director of the Pima County Department of Transportation, responded to questions about the new intersection, which is common in Michigan.

Q: Who made the decision on the intersection?

A: Multiple agencies were involved.

The Pima County Department of Transportation recommended the indirect-left concept based on engineering, traffic and safety studies as a way to respond to congestion at the intersection.

The Arizona Department of Transportation had to agree, because Oracle is a state highway.

And the Regional Transportation Authority provided the funding.

Once the three governments agreed on the concept, meetings were held with neighbors and affected businesses to address their concerns.

Q: How long has this proposal been under consideration?

A: Over three years.

Q: What were the main reasons for choosing this traffic measure?

A: Because Oracle Road is owned by the state, improvements had to be made to Ina Road to address this heavy congestion, long delays and safety issues. This alternative worked the best.

The other alternative was to do nothing, because ADOT had no plans to improve Oracle Road at Ina.

Q: How much traffic goes through the Ina-Oracle intersection in a day?

A: About 96,000 vehicles daily.

Q: How much did it cost to reconfigure the intersection?

A. About $5 million.

Contact reporter Joe Ferguson at jferguson@azstarnet.com or 573-4346. Follow him on Twitter @JoeFerguson.

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